High-temperature vapor-pressure recorder and regulator



June 14,1927. I 1,632,152

K. TATE HlGH TEMPERATURE VAPOR PRESSURE RECORDER AND REGULATOR Filed July 12', 1926 INVENTOR 4- ATTORNEY measuring for the measurementsofihigl 1 .sionathermomter -t Patented June 14, 1927.

=toi-aswpyronietersi a It --cthe:;- gene1 w ovideaiarpyrome' tion and"; operation;

-;the proiiision o'fga. some, 7 .Q slon thermometer type, which is,,

:th'anL waszrherejtofo, mentszo'f "this class Foryathermeasurement of ,telil L at: 4

"islets u,

cause of the high p atnsuch.i-t axperaturi siandi was general pr ctice to use optlcal or electricalrpyrofmti? of lowerin the vapor-pressure of the mercury by a dition of less volatile metals, in

2 accordance with the well known law of Raoult.

While in theory metals other than mercury ma come under consideration or may be actua 1y usedas the basic part of a mixture or an alloy having a vapor-pressure suitable for the purposes of the invention, mercury is for reasons of ractical require ments the only metal available. Although there are various metals that may be added to mercury to reduce the vapor-pressure thereof, I consider thallium as the only metal which'satisfies ractical requirements.

My invention, brie y stated, isthe application of a mercury-thallium alloy as the 40 active thermometric fluid in a container of highly heat resistive material.

Alloys of mercury and thallium are known and in fact the application of a mercury-thallium alloy as active thermometric fluid is disclosed in the patent to Steinmetz No. 935,940. However, in that case .the question of vapor-pressure is not involved and the particular alloy or amalgam was chosen for the purpose of obtaining a thermometric liquid of low freezing point. 4

For a full understanding of the invention, the principle of operation on which it is based and its advantages, reference is made to the accompanying drawing which is an The present invention based on the ide t capillaries measuring about .196 O; D. and the bulb space had a volume of the order of 1 cc.

With the aid of a suitable fillin apparatus the entire system is preferably rst entirely filled with the liquid and then a small amount i. e. about 4 cc. of the liquid is removed to provide for the vapor space in the bulb.

The capillar is preferably welded into the fire tube w ere it issues from the latter, as indicated by the numeral 6.

Generally stated, the decrease in the vaporspressure of the actuating fluid is substantially proportional to the precentage increase of the thallium in the alloy. However, due toa continued rise of the freezing oint or the solidification point after an mitial fall, a-practical limit is reached near the ratio of 40% of thallium and of mercury, which composition freezes at about +38% F. and produces a va or-pressure approximately one half that 0 pure mercury'.

If. it were practically feasible' to use the,

essary and the rise of the freezing point would not be objectionable. However, inasmuch as it is for. practical considerations essential that a single fluid be used for trans- Q I I 1,032,152

mitting as well as for actuating purposes, the composition must be so chosen that transmission is not impeded at ordinary temperatures. E

= In the foregoingI have made special rercrence to vapor-pressure instruments. It is understood. however, that the advantage of vapor-pressures i. e. vapor-pressures in ex:

cess of those obtained with mercury for ranges above 1000 F.

I claim as my invention:

1. In a' thermometric device of the expansion thermometer type, the combination with a fluid-pressure container and fluid connection thereto, of a bulb consisting of a material capable of resisting temperatures in excess of 1000 F. and a mercury-thallium alloy therein containing substantially 60% mercury and substantially 40% thallium.

2. In a thermometric device of the expansionthermometer type, a fluid-pressure system including a bul a pressure-responsive container, a capillary interconnecting the same and a mercury-thallium alloy substantially filling the system, the alloy being fluid at ordinary temperatures and havinlg a vapor-pressure materially lower than t at of mercury.

3. In a thermometric device of the expansion thermometer t pe, a fluid-pressure sive container, a capillar interconnecting the same and a mercury-thallium alloy filling the system so as to leave a vapor-space in the bulb, the alloy being fluid at ordinary temperatures and having a vapor-pressure materially lower than that of mercury.

4. n a thermometric device of the expansion thermometer t 'pe, a fluid-pressure system including a bul a pressure-responslvecontainer, a capillary interconnecting the same and a mercury-thallium alloy substantially filling the system and havin a vapor-pressure approximately one half t at of mercury.

5. In a thermometric device of the expansion thermometer type, the combination with afluid pressure container and fluid connection thereto, of a bulb consisting of a material capable'fof resisting temperatures in excess of 1000 F. and a mercury-thallium alloy'therein containing more than 10% of thallium and not materially exceeding 40% of thallium. I y

In testimony whereof I aflix mysignature.

KENNETH L. TATE.

'system including a-bul a pressure-respon- 

